The project also is going to cost $5 million more than expected.

The discovery of a building foundation and artifacts from the late 1800s delayed construction of bus barns at the Indianapolis Downtown Transit Center.(Photo: Provided by IndyGo)

Archaeological discoveries in May have added seven months and $5 million in extra costs to IndyGo's Downtown bus transit center project.

The transit center, which will become a hub for most of the city's bus lines, is now on pace to be completed in mid-June. The project was supposed to be finished in November, but construction halted when excavators found the remnants of previous buildings at the site. The transit center is being built on Washington Street between Alabama and Delaware streets.

The estimated cost of the project has risen from $20 million to $26.5 million, largely because of the archaeological findings, IndyGo spokesman Bryan Luellen said. A federal grant is covering $13.5 million, but IndyGo will have to pay for the unexpected costs.

The transit hub will be a glassy 14,000-square-foot building with 19 bus bays and retail. The project is expected to shorten commutes for bus riders by enabling more efficient routes.

The most significant historical findings at the site were foundations of previous buildings, dating perhaps to the 1800s. The long-forgotten building foundations didn't necessarily warrant a monthslong delay, Luellen said, but construction crews couldn't work around them.

"It's just a function of where the stuff is located that they couldn't continue working," Luellen said.

Work resumed at a normal pace in October, Luellen said.

"We're pretty much cleared of the archaeological monitoring, and that was the delay," he said.

Archaeologists examined materials such as glass and flatware and sent them to labs to be processed and cataloged. IndyGo will issue a report after the project is completed.

"We're actually working on a curation plan to showcase what it is that we found," Luellen said. "We hope that will be ready in the next few months."

IndyGo is in talks with the Indiana State Museum to display artifacts, he said.

In addition to construction delays, the archaeological findings pushed back changes to IndyGo's bus lines. IndyGo is planning to alter 27 of its 31 routes but not until the new transit center opens.

"We weren't going to pull the trigger on route changes until the center was ready," Luellen said.

Call Star reporter James Briggs at (317) 444-6307. Follow him on Twitter: @JamesEBriggs.